Method for producing a shaped part, and a shaped part

ABSTRACT

A method for producing a shaped part may include providing a first layer consisting of a first sheet metal material and at least a second layer consisting of a second sheet metal material, forming a preliminary composite comprising the first layer and the at least second layer, plating the preliminary composite, and forming the preliminary composite to obtain the shaped part using a flow turning, compression or deep drawing method. The plating may be done before or during the forming process. At least one of the first layer or the second layer may be heated for the plating and/or the forming. The shaped part may be formed by compressing the preliminary composite with a pressing body, and the pressing body may be moved parallel or perpendicular to an axis of symmetry during the compression.”

PRIOR ART

The invention relates to a method for producing a shaped part, and to ashaped part.

In particular, the present invention relates to a method in which amaterial sequence in the shaped part is deliberately assembled byplating. Plating typically ensures that a first layer or a base body iscovered by at least a second layer of another material by creating anintegrally bonded composite between the first and the at least secondlayer by a mechanical action, such as a rolling treatment. It istherefore usually intended to cover a base body with a more valuablematerial than the base body or—as is disclosed for example in thepublication DE 10 2012 100 278 A1—to create in the fabricated shapedpart a material progression with different physical properties. Theshaped part formed from a band, in which the desired integrally bondedcomposite between the first and the second layer was created in advanceby a costly plating of slabs and hot rolling, is processed such that thedesired material progression emerges in the fabricated shaped part.

DISCLOSURE OF THE INVENTION

One problem which the present invention proposes to solve is to providea method with which the production of shaped parts consisting of severallayers is simplified and, in particular, individualized.

The present invention solves the problem by a method for producing ashaped part having the following method steps:

-   -   providing a first layer consisting of a first sheet metal        material and at least a second layer consisting of a second        sheet metal material,    -   forming a preliminary composite comprising the first layer and        the at least second layer    -   plating the preliminary composite    -   forming the preliminary composite to obtain the shaped part        using a flow turning, compression or deep drawing method,

wherein the plating is done before or during the forming process.

As compared to the prior art, with the method according to the inventionthe plating and the forming of sheet metal materials are done in a jointwork step or alternatively a plating of sheet metal materials is donewithout having to perform the costly hot rolling process of slabs and aseparate forming is done. In this way, a fabrication of the shaped partis not only made faster, but also the shaped part can be individualizedmore easily. Finally, one is not bound by the arrangements dictated inthe coil or the thickness relationships of the first and at least secondlayer used there. Instead, depending on the intended purpose of thedesired shaped part, the first layer and at least second layer of sheetmetal materials can be correspondingly provided individually, forexample in regard to their thickness.

Preferably, the forming is done by a projecting, flow turning and/orcompression. For example, the forming produces a hub, for example, forthe fabricated component. It is provided in particular that the firstand the at least second layer of sheet metal materials are laid againstone another or on top of one another in the preliminary composite,without there being present a relatively large-area integrally bondedconnection. It is conceivable that the first and/or the at least secondlayer of sheet metal materials are formed such that in addition to theintegrally bonded connection the forming realizes a form fit between thefirst and the second layer. In particular, it is provided that formingand plating are carried out simultaneously in a joint, preferablyseparate, work step. Alternatively, prior to the forming by a deepdrawing, projecting, flow turning and/or compression, a first and atleast second layer of sheet metal materials are laid against or on topof one another, being integrally bonded to each other by plating.

Advantageous embodiments and modifications of the invention will befound in the dependent claims and the description making reference tothe drawings.

According to another embodiment of the present invention, it is providedthat the first layer and/or the at least second layer of sheet metalmaterials are heated for the plating. It is also conceivable that theplating is done without prior heating, i.e., in the cold state.Furthermore, it is conceivable that the first and/or at least secondlayer of sheet metal materials is heated specifically in particularranges. Thanks to the heating, the forming and plating or only theplating can be advantageously facilitated.

According to another embodiment of the present invention, it is providedthat a shaped part is formed which is entirely rotationally symmetricalto an axis of symmetry. It is also conceivable that only a partialregion of the shaped part has a rotationally symmetrical region.Furthermore, it is conceivable that a rotationally asymmetrical shapedpart is formed by nonround compression. In nonround compression, forexample, a rotationally asymmetrical shaped part is realized by a force-or path-controlled feeding of the pressing roller.

According to another embodiment of the present invention, it is providedthat a pressing body, such as a pressing roller, is used during thecompression method, the pressing body being moved parallel and/orperpendicular to the planned axis of symmetry during the compressionmethod. In particular, the pressing body during the forming process liesagainst the preliminary composite, and by moving the pressing body theforming essential for the forming of the planned shaped part isrealized. Preferably, the first and/or at least second layer of sheetmetal materials is realized by several pressing bodies, for examplepressing bodies situated opposite each other. For example, the pressingbody has a discus-shaped base body, whose closing edge comes intocontact with the first and/or at least second layer of sheet metalmaterials during the compression method.

According to another embodiment of the present invention, it is providedthat a second sheet metal material is used which is different from thefirst sheet metal material, in particular an iron material being used asthe first sheet metal material and at least second sheet metal materialor a nonferrous material being used as the first sheet metal materialand as the second sheet metal material. It is conceivable that the ironmaterial used as the second sheet metal material is different from theiron material used as the first sheet metal material in terms ofphysical properties, such as ductility, hardness, or shaping ability.For example, the first sheet metal material and the at least secondsheet metal material differ in terms of carbon content. Preferably, thefirst layer of the sheet metal material comprises an iron material witha carbon fraction of more than 0.1 wt. %, preferably more than 0.25 wt.% and especially preferably approximately 0.5 wt. %. In this way, ashaped part can be realized whose interior sheet metal materialcomposition ensures for example a comparatively high hardness, while theexterior sheet metal material composition has a lower carbon fraction ascompared to the interior sheet metal material composition and thus mayprovide a greater ductility.

According to another embodiment of the present invention, it is providedthat

-   -   the first layer comprises an iron material and the at least        second layer a nonferrous material, or    -   the first layer comprises a nonferrous material and the at least        second layer an iron material. In this way, the range of        potential sheet metal material compositions in the fabricated        shaped part can be enlarged advantageously.

According to another embodiment of the present invention, it is providedthat the first layer and the at least second layer of sheet metalmaterials are secured for the plating and optionally the forming. Forthis, the first and/or the at least second layer are clamped for examplein a device and/or the layers are pressed together. In this way, it isadvantageously assured that the first and/or the second layer do notslip during the plating and optionally the forming. Preferably, anabutment or hold-down is used for the securing of the first and/or atleast second layer of sheet metal materials. It is also conceivable thatthe first layer and the at least second layer are fixed to each otherfor example by a spot welding or clamping together to form thepreliminary composite for transport and positioning purposes.

According to another embodiment of the present invention, it is providedthat the preliminary composite is arranged in a die. Preferably, the diecomprises a receiving region, inside which the preliminary composite isarranged for the plating and optionally at least partly for the forming.In particular, the die is designed such that it counteracts a sidewaysdisplacement of the preliminary composite during the processing.

According to another embodiment of the present invention, it is providedthat the preliminary composite is clamped in the die by means of aspring element. By means of the springs, fixation can be provided in anadvantageous manner. In this case, a spring force of the spring elementis directed at the receiving region of the die. Preferably, the diecomprises several spring elements, which are arranged and/or configuredsuch that the preliminary composite is centered inside the die insidethe receiving area by the spring elements. In addition, the springelements can provide a resetting of the nonplated and possibly nonformedparts of the composite.

According to another embodiment of the present invention, it is providedthat the preliminary composite for the plating and optionally for theforming is arranged in an at least partly contoured receiving region ofthe die. For example, the receiving region comprises a contoured bottomregion, in order to advantageously provide a better intermeshing duringthe plating and optionally the forming.

According to another embodiment of the present invention, it is providedthat the preliminary composite for the plating and the forming isarranged on a shape-determining tool body, such as a round blank. Forexample, an outer contour of the shape-determining tool body establishesthe shape of a bulge or a cavity in the fabricated shaped part.Preferably, the preliminary composite is pressed by the pressing bodyagainst an outer side of the shape-determining tool body until theplanned shaped part has been formed. It is preferably provided that thepreliminary composite is arranged between the shape-determining toolbody and an abutment or hold-down, the shape-determining tool bodyand/or the abutment or the hold-down being subjected to force so as toprovide for a fixation of the preliminary composite.

Another subject of the present invention is a shaped part fabricated bya method according to the invention, wherein the first layer as sheetmetal material comprises an iron material with a carbon fraction of morethan 0.1 wt. %, preferably more than 0.25 wt. % and especiallypreferably substantially 0.5 wt. %.

As compared to the shaped parts of the prior art, it is possible toprovide a relatively high hardness of the fabricated shaped part in anadvantageous manner with the increased carbon fraction. Preferably, bythe choice of the at least second layer with a lower carbon fractionthan the first layer, one can realize a greater ductility in thefabricated shaped part, especially on its exterior. It is conceivablethat the fabricated shaped part comprises a hollow body, whose insidecomprises at least partly the first layer.

The invention is not confined to two layers of sheet metal materials.

According to another embodiment of the present invention, it is providedthat the shaped part is a joint head.

Further details, features and benefits of the invention will emerge fromthe drawings, as well as the following description of preferredembodiments with the aid of the drawings. The drawings illustrate onlysample embodiments of the invention, not limiting the idea of theinvention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a die suitable for a method for producing a shaped partaccording to a first sample embodiment of the present invention.

FIGS. 2a to d show schematically consecutive snapshots of the method forproducing a shaped part according to a second sample embodiment of thepresent invention.

FIGS. 3a to e show schematically consecutive snapshots of a method forproducing a shaped part according to a third sample embodiment of thepresent invention.

EMBODIMENTS OF THE INVENTION

In the different figures the same parts are always given the samereference numbers and therefore in general are also only designated ormentioned once in each case.

FIG. 1 shows a die 10 suitable for a method for producing a shaped partaccording to a first sample embodiment of the present invention. Inparticular, this involves a method in which a first layer 1 of a firstsheet metal material is plated with a second layer 2 of a second sheetmetal material, i.e., by mechanical action an integrally bonded coveringof the first layer 1 with the second layer 2 is created. Preferably, thesecond sheet metal material is one which is more precious or valuablethan the first sheet metal material, or a shaped part is to be realizedhaving different physical properties on different levels. In order toproduce the shaped part consisting of the first layer 1 and the secondlayer 2, it is provided that the plating, especially an integrallybonded assembling of the first and second layer 1 and 2 into acomposite, accompanying the plating, occurs at first in a first workstep. Not represented here, but familiar to the skilled person, therethen occurs the forming of the composite, which occurs in a second,separate work step, the forming involving a compression or deep drawingmethod by which the form of the shaped part is realized. In this way,one may advantageously do without a costly hot rolling of slabs stackedon each other in order to initially produce a semi-finished product inadvance. For the fixing of the first layer 1 and the second layer 2 ofsheet metal materials during the plating, the die 10 is preferablyprovided, where the die 10 has a receiving region to receive apreliminary composite consisting of the first layer 1 and the secondlayer 2. In particular, the die 10 comprises several spring elements 12,with which the first layer 1 and the second layer 2 are clamped in thedie 10. In the sample embodiment represented in FIG. 1, spring elements12 are arranged on an inner side 11′ of the receiving region 11 aroundthe periphery, especially at equal distances from each other. Forexample, the spring elements 12 each comprise two coil springs 13, whichare attached to the inner side 11′ of the receiving region 11. The endof the spring element 12 facing the first or the second layer 1 or 2 ispreferably adapted to a radius of curvature which is dictated by thedisk-shaped first and second layers 1 and 2. Furthermore, it is providedthat a bottom region 11″ of the receiving region 11 has contours inorder to improve an intermeshing of the layers being plated, which mayalso comprise more than two layers of sheet metal materials. Usingsuitable means not represented here, one or both layers may be heatedprior to the plating if needed.

FIGS. 2a to d show schematically consecutive snapshots of the method forproducing a shaped part according to a second sample embodiment of thepresent invention. For example, a die 10 is used for this, asillustrated in FIG. 1. For the plating, it is provided that thedisk-shaped first layer 1 and the second layer 2 are arranged one on topof the other inside the receiving region 11 of the die 10. The first andthe second layer 1 and 2 have the same diameter here. In particular, thefirst and the second layer 1 and 2 are placed congruently on top of eachother. It is conceivable that the upper second layer 2 terminates flushwith an upper edge of the receiving region 11. After the first andsecond layer 1 and 2 are placed in the receiving region 11, wherein oneor both layers may be heated if necessary by suitable means notrepresented here, the simultaneous forming and plating begins in thattwo discus-shaped pressing bodies 20 press against the upper, here thesecond, layer 2, and are moved along a direction running substantiallyparallel to a principal plane of extension of the layers or a directionrunning parallel to the bottom region 1″ of the receiving region 11. Inparticular, this movement is repeated for as long as it takes to producethe desired shape of the shaped part being fabricated. In the presentcase, the fabricated shaped part comprises a hub.

FIGS. 3a to e show schematically consecutive snapshots of a method forproducing a shaped part according to a third sample embodiment of thepresent invention. It is provided here that the first layer 1 and thesecond layer 2 are placed one on top of the other on a round blank 31,especially on an end piece of a round blank 31. Preferably, the roundblank 31 tapers in the direction of the end piece on which the firstlayer 1 and the second layer 2 are lying. In particular, it is providedthat the diameter of the first layer 1 or the second layer 2 is largerthan a maximum diameter of the round blank 31. In this way, the firstand second layer 1 and 2 placed on the round blank 31 stick out withrespect to a side surface of the round blank 31. For the fixation, ahold-down 32 is provided, the hold-down 32 in a fixation position actingon the second layer 2 and thus holding together the first layer 1 andthe second layer 2. By means of the hold-down 32, the first and thesecond layer 1 and 2 are preferably fixed in common. By suitable meansnot represented here, one or both layers may be heated if needed.Furthermore, it is provided that a flow turning process is performed bymeans of two, in particular discus-shaped, pressing bodies 20, by whicha plating on the one hand and the forming on the other hand is achieved.In this case, the pressing bodies 20 are moved along a pathsubstantially parallel to an axis of the round blank or along a pathdictated by an outer side of the round blank, with the round blank beingentirely rotationally symmetrical to the axis. Thanks to the flowturning, in particular, the first and the second layer 1 and 2 after theforming lie jointly against an outer side of the round blank 32 and thusthe fabricated shaped part shown in FIG. 3e is provided.

LIST OF REFERENCE NUMBERS

1 First layer

2 Second layer

10 Die

11 Receiving region

11′ Bottom region

11″ Inner side

12 Spring elements

13 Coil spring

20 Pressing body

31 Round blank

32 Hold-down

1.-12. (canceled)
 13. A method for producing a shaped part, the methodcomprising: providing a first layer comprising a first sheet metalmaterial and a second layer comprising a second sheet metal material;forming a preliminary composite that includes the first layer and thesecond layer; plating the preliminary composite; and forming thepreliminary composite to obtain the shaped part by way of flow turning,compression, or deep drawing, wherein plating the preliminary compositeis performed before or during the forming of the preliminary compositeto obtain the shaped part.
 14. The method of claim 13 comprising heatingat least one of the first layer or the second layer for the plating. 15.The method of claim 13 wherein the preliminary composite is formed suchthat the shaped part is rotationally symmetrical to an axis of symmetryat least in some regions.
 16. The method of claim 15 wherein the shapedpart is formed by compressing the preliminary composite with a pressingbody, wherein the pressing body is moved parallel or perpendicular tothe axis of symmetry during the compression.
 17. The method of claim 13wherein the first sheet metal material is different than the secondsheet metal material.
 18. The method of claim 17 wherein the first sheetmetal material and the second sheet metal material are comprised of aniron material.
 19. The method of claim 17 wherein the first sheet metalmaterial and the second sheet metal material are comprised of anonferrous material.
 20. The method of claim 13 comprising securing thefirst layer and the second layer for the plating.
 21. The method ofclaim 13 comprising positioning the preliminary composite in a die. 22.The method of claim 21 comprising clamping the preliminary composite inthe die by way of a spring element.
 23. The method of claim 13comprising positioning the preliminary composite in an at leastpartially-contoured receiving region of a die for the plating.
 24. Themethod of claim 13 comprising positioning the preliminary composite on ashape-determining tool body for the plating and the forming.
 25. Themethod of claim 24 wherein the shape-determining tool body is a roundblank.
 26. A shaped part fabricated by a method comprising: providing afirst layer comprising a first sheet metal material and a second layercomprising a second sheet metal material, wherein the first sheet metalmaterial comprises an iron material with a carbon fraction of more than0.1% by weight; forming a preliminary composite that includes the firstlayer and the second layer; plating the preliminary composite; andforming the preliminary composite to obtain the shaped part by way offlow turning, compression, or deep drawing, wherein plating thepreliminary composite is performed before or during the forming of thepreliminary composite to obtain the shaped part.
 27. The shaped part ofclaim 26 wherein the carbon fraction in the iron material of the firstsheet metal material is more than 0.25% by weight.
 28. The shaped partof claim 26 wherein the carbon fraction in the iron material of thefirst sheet metal material is more than 0.5% by weight.
 29. The shapedpart of claim 26 configured as a joint head.